Apparatus for forming spiral steel pipe

ABSTRACT

An apparatus for forming spiral steel pipe by separate type forming rolls which is characterized by stands carrying rolls for forming the inner and outer surfaces of the steel pipe, the stands being each split into two portions in a direction perpendicular to the axis of the steel pipe to be formed, one of the two portions being a fixed stand formed with a smaller length than the width of material plate for the intended steel pipe and the other portion being a stand movable in the axial direction of the steel pipe to be formed.

United States Patent [191 Tanaka et al.

[ APPARATUS FOR FORMING SPIRAL STEEL PIPE [75] Inventors: YasuhikoTanaka; Yasumi Shimazaki; Kenii Hagiwara, all of Kitakyushu, Japan [73]Assignee: Nippon Steel Corporation, Tokyo,

Japan [22] Filed: June 29, 1972 [21] Appl. No.: 267,459

['30] Foreign Application Priority Data June 30, 1971 Japan 46-56783[52] US. Cl. 72/135, 29/477.3 [51] Int. Cl B2lf 3/02 [58] Field ofSearch 72/49, 50, 135, 368, 371;

[56] References Cited UNITED STATES PATENTS 3,407,639 l0/l968 Kehne72/135 [451 May 7,1974

3,606,783 9/1971 Lewis 29/477.3

Primary Examiner-Charles W. Lanham Assistant Examiner-Robert M RogersAttorney, Agent, or Firm-Wenderoth, Lind & Ponack [5 7] ABSTRACT Anapparatus for forming spiral steel pipe by separate type forming rollswhich is characterized by stands carrying rolls for forming the innerand outer surfaces of the steel pipe, the stands being each split intotwo portionsin a direction perpendicular to the axis of the steel pipeto be formed, one of the two portions being a fixed stand formed with asmaller length thaii th e width of material plate for the intended steelpipe and the other portion being a stand movable in the axial directionof the steel pipe to be formed.

4 Claims, 5 Drawing Figures msmanm 1 m4 3308.862

, FLUID PRESSU CYLINDER sYs APPARATUS FOR FORMING SPIRAL STEEL PIPEBACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to an apparatus for forming spiral steel pipe and moreparticularly to an apparatus for forming spiral steel pipe whichcomprises separate rolls for forming the inner and outer surfaces of thespiral pipe.

2. Description of the Prior Art In an apparatus for forming spiral steelpipe by spirally bending steel plate, insufficient bending of a steelplate end usually gives rise, as shown in FIG. 1, to an abnormalbulging, or peaking 4 in the vicinity of the weld in the plate 2 of theformed steel pipe 1. This abnormal deformation 4 lowers the strength ofthe welded joint and spoils the beauty of the appearance, thus beingvery undesirable in respect of the product value.

It is said however that a relatively small amount of peaking takes placein forming steel pipe by means of so-called separate type forming rollswhich comprise a multiplicity of separate rolls for forming the innerand outer surfaces of the steel pipe. Nevertheless, on occasion thepeaking exceeds two millimeters. A typical apparatus for forming spiralsteel pipe by separate forming rolls comprises, as shown in FIG. 2, aset of innersurface forming rolls l2 fitted to a stand 11 and two setsof outer-surface forming rolls 15 and 16 installed on stands 13 and 14respectively, the three sets of rolls being in triangular arrangement,with the firstmentioned set of rolls 12 at the vertex of the triangleand the two other sets of rolls 15 and 16 at the opposed ends of thebase thereof. The three sets of forming'rolls 12, 15 and 16 act on thematerial plate 2 so as to bend it spirally. As shown in FIG. 4, however,the steel plate SUMMARY OF THE INVENTION The present invention obviatesthese problems by providing a forming apparatus which always enables aside end of a steel plate of any width to engageflwith rolls for formingthe inner and outer surfaces. The invention contemplates an apparatusfor forming spiral steel plate by separate type forming rolls which ischaracterized by having stands carrying rolls for forming the inner andouter surfaces of the steel pipe, the stands being each split into twoportions in a direction perpendicular to the axis of the steel pipe tobe formed, one

.of the two portions being a fixed stand formed with a smallerlengththan the width of the material plate for the intended steel pipeand the other portion being a stand which is movable in the axialdirection of the steel pipe to be formed.

An object of the present invention is to provide an apparatus forforming spiral steel pipe by bending plate material in a manner so as toinhibit abnormal deforma- 2 tion such as peaking from taking place atthe welded joint. p Another object of the invention is to provide anapparatus for forming spiral steel pipe which is effective to preventthe abnormal deformation from ocurring at the welded joint and alsosimple in construction and easy to operate.

These and other objects of the present invention will be more clearlyunderstood when the following description of a preferred embodiment isread in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an abnormaldeformation caused by a conventional apparatus.

FIG. 2 is a side view of an apparatus for forming spiv thereof, thestands being disposed in two rows A and B extending in parallel in theaxial direction of the pipe 1 to be formed, as a matter of functionalnecessity. The

and 20 are in alignment with the fixed stands 17 and 18- respectively'and located on the rear side of the fixed stands 1.7 and 18, that is, onthe leading side thereof with respect to the direction in which the pipe1 being formed advances. The stands 19 and 20 are 'movable up to onepitch of the outer-surface forming rolls 15 and 16 in the axialdirection of the pipe 1 to beformed. Any

stand movement exceeding one pitch of the rolls is not necessary at allin view of the fact that the major object of the apparatus of thepresent invention is to prevent abnormal defonnation at the joint byplacing an entire steel plate end on rolls without fail. The shift ofthe movable stands 19 and 20 can be effected by a relative slide betweensurfaces or by means of rollers, which should be construed asnon-limitative and any other desired means may be employed for thepurpose. Devices 21 and 22 which may be used for shifting the movablestands 19 and 20 employ a screw mechanism in this embodiment-That is,threaded drive shafts 23 and 24 extending in the longitudinal directionof the movable stands'l9 and 20 are secured to .the rear ends of themovable stands 19 and 20 respectively. The drive shafts 23 and 24 arefitted with threaded sleeves 25 and 26 respectively and rotation of thesleeves will advance the movable stands 19 and 20 through the driveshafts 23 and 24. Also it is possible as a matter of course to apply afluid pressure cylinder system to the shift adjusting devices 21 and 22.Furthermore, the lengths of the fixed stands 17 and 18 are notparticularly limited so long as the said lengths are smaller than thewidth of the plate material for the steel pipeto be formed. If the fixedstands should be wider than the plate material,

the function and effect of the movable stands in the apwould be lost.

The stand which carries the inner-surface forming rolls is also composedof a fixed stand and a movable stand in entirely the same manner as thestands for the outer-surface forming rolls.

Operation of the heretofore described apparatus of the present inventionwhen the steel plate material for the steel pipe to be formed issupplied to the apparatus will now be described by reference to FIG. 4.(For conveneince of illustration, only the operation of the outersurfaceforming rolls and their stands will be described. However, the operationis entirely the same as the operation of the inner-surface forming rollsand the stand therefor.) When a side end 3 of the steel plate 2 is notmounted on the forming rolls l5 and 16 but positioned in the inter-rollspace, the screw mechanism of the devices 21 and 22 for adjusting theshift of the movable stands 19 and is operated to shift the movablestands l9 and 20 to an adequate position (indicated by dashed line inthe illustrated embodiment) within the pitch of the outer-surfaceforming rolls in the axial direction of the steel pipe 1 to be formed,thereby placing the side end} of the material steel plate 2 on theoutersurface forming rolls l5 and 16. The direction of advance of thesteel pipe being formed is denoted by a, the direction of feeding thesteel plate 2, by b, and the direction of shifting the movable stands 19and 20, by

It will be apparent from the foregoing description that, according tothe apparatus of the present invention, the material plate for the steelpipe to be formed can be subjected to formation with a side end thereofalways placed on the outer-surface forming rolls so that the abnormaldeformation which is called peaking can be prevented from taking placeat the pipe joint. Thus, the present apparatus displays an exceedinglydesirable effect in enabling the produced steel pipe to have a highquality.

What is claimed is:

1. An apparatus for forming spiral steel pipe by separate type formingrolls which is characterized by stands carrying rolls for forming theinner and outer surfaces of the steel pipe, the stands being each splitinto two portions in a direction perpendicular to the axis of the steelpipe to be formed, one of the two portions as a fixed stand formed witha smaller length than the width of the material plate for the intendedsteel pipe and the other portion as a stand movable in the axialdirection of the steel pipe to be formed.

2. An apparatus as defined in claim 1, characterized in that the shiftof the movable stands in the axial direction of the steel pipe to beformed is within one pitch of the forming rolls.

3. An apparatus as defined in claim 1, characterized in that the movablestands are shifted in the axial direction of the intended steel pipe bymeans of a screw mechanism.

4. An apparatus as defined in claim 1, characterized in that the movablestands are moved axially of the intended steel pipe by means of a fluidpressure cylinder system.

1. An apparatus for forming spiral steel pipe by separate type formingrolls which is characterized by stands carrying rolls for forming theinner and outer surfaces of the steel pipe, the stands being each splitinto two portions in a direction perpendicular to the axis of the steelpipe to be formed, one of the two portions as a fixed stand formed witha smaller length than the width of the material plate for the intendedsteel pipe and the other portion as a stand movable in the axialdirection of the steel pipe to be formed.
 2. An apparatus as defined inclaim 1, characterized in that the shift of the movable stands in theaxial direction of the steel pipe to be formed is within one pitch ofthe forming rolls.
 3. An apparatus as defined in claim 1, characterizedin that the movable stands are shifted in the axial direction of theintended steel pipe by means of a screw mechanism.
 4. An apparatus asdefined in claim 1, characterized in that the movable stands are movedaxially of the intended steel pipe by means of a fluid pressure cylindersystem.